1. Field of the Invention
The present invention relates to a loudspeaker damper, used for a loudspeaker or the like, and a method of mounting the loudspeaker damper.
2. Description of the Related Art
A damper playing the role of damping a voice coil of a vibrating portion so as to properly holding the voice coil in a magnetic pole space between a pole and a plate has been used for a loudspeaker in related art. FIGS. 15A to 15C are diagrams showing the shapes of dampers according to the related art, in which FIG. 15A shows a track-shaped damper, FIG. 15B shows an inner damper, and FIG. 15C shows a butterfly damper.
In the case of reducing the width of a diaphragm of a loudspeaker, a method may be used in which, as shown in FIG. 15A, a track-shaped damper 151 is used in the state of surrounding the outer periphery of a track-shaped voice coil 152 having a minor diameter and a major diameter. According to the method in which the track-shaped damper 151 is used, the width of the diaphragm can be reduced to a width roughly equivalent to the minor diameter of the track-shaped damper 151.
Besides, as shown in FIG. 15B, there may be adopted a method in which a damper 153 is used on the inside of a track-shaped voice coil 154 having a minor diameter and a major diameter, or a method in which a damper 155 is used on the inside of a circular voice coil 156. According to the method in which the damper 153 is used on the inside of the track-shaped voice coil 154, the width of the diaphragm can be reduced to a width roughly equivalent to the minor diameter of the track-shaped voice coil 154 or the diameter of the circular voice coil 156.
Further, as shown in FIG. 15C, a method has been proposed in which use is made of a butterfly damper 157 having a frame portion 158 for supporting the outer periphery of a voice coil 161, and a pair of support portions 159 and 160 for supporting the frame portion 158 from both sides in the major diameter direction. According to the method in which the butterfly damper 157 is used, there is no support in the minor diameter direction, so that the minimum resonance frequency F0 of the diaphragm of the loudspeaker is not raised, and the width of the diaphragm can be reduced. Furthermore, there have been proposed a method in which the damper is eliminated and a method in which the damper is simplified. According to these methods, also, a sufficiently low minimum resonance frequency F0 can be obtained, like in the case of using the butterfly damper.
In addition, in order to realize a sound wave radiation such that the frequency response is flat and the harmonic distortion is little over the range from a low frequency region to a high frequency region, an electroacoustic transducer has been proposed in which a hook type suspension having one end fixed in the longitudinal direction of a voice coil and the other end fixed to a frame supporting a magnetic circuit is provided at each of both ends of the voice coil (Japanese Patent Laid-open No. 2003-47089).
Besides, a loudspeaker damper has been proposed in which a voice coil has a major axis direction and a minor axis direction, a plurality of movable arms are formed along the major axis direction, a reinforcement member bridgingly provided between two movable arms of the plurality of movable arms is disposed substantially in parallel to the minor axis direction, in the vicinity of the voice coil support portion side (Japanese Patent No. 3506855).